Key pathological features characterize minimal change disease-like IgA nephropathy.

AIMS: A subset of IgA nephropathy (IgAN) patients exhibiting minimal change disease (MCD) like features present with nephrotic-range proteinuria and warrants immunosuppressive therapy (IST). However, the diagnosis of MCD-like IgAN varied by reports. We aimed to identify the key pathological features of MCD-like IgAN. METHODS: In this cohort, 228 patients had biopsy-proven IgAN from 2009 to 2021, of which 44 without segmental sclerosis were enrolled. Patients were classified into segmental (< 50% glomerular capillary loop involvement) or global (> 50%) foot process effacement (FPE) groups. We further stratified them according to the usage of immunosuppressant therapy after biopsy. Clinical manifestations, treatment response, and renal outcome were compared. RESULTS: 26 cases (59.1%) were classified as segmental FPE group and 18 cases (40.9%) as global FPE group. The global FPE group had more severe proteinuria (11.48 [2.60, 15.29] vs. 0.97 [0.14, 1.67] g/g, p = 0.001) and had a higher proportion of complete remission (81.8% vs. 20%, p = 0.018). In the global FPE group, patients without IST experienced more rapid downward eGFR change than the IST-treated population (-0.38 [-1.24, 0.06] vs. 1.26 [-0.17, 3.20]mL/min/1.73 m2/month, p = 0.004). CONCLUSIONS: The absence of segmental sclerosis and the presence of global FPE are valuable pathological features that assist in identifying MCD-like IgAN.

Timing of kidney biopsy in type 2 diabetic patients: a stepwise approach.

BACKGROUND: Diabetic nephropathy (DN) is the most prevalent cause of renal disease in type 2 diabetic patients and is usually diagnosed clinically. A kidney biopsy is considered when non-diabetic renal disease (NDRD) is suspected, such as rapid progression in renal function impairment and severe proteinuria. Still, there is yet no consensus on the timing of kidney biopsy in type 2 diabetic patients. This study aims to identify markers that can help differentiate between DN and NDRD and guide the decision of kidney biopsy. METHODS: We retrospectively reviewed patients with type 2 diabetes who received kidney biopsy from 2008 to 2017 at Taipei Veterans General Hospital. Ophthalmologist consultation and outpatient records, diagnosis of kidney biopsy, laboratory data, and clinical characteristics were collected. RESULTS: This study enrolled 160 type 2 diabetic patients, among which 120 (75%) had isolated DN and 40 (25%) had NDRD ± DN (26 had isolated NDRD, and 14 had NDRD superimposed on DN). In multivariate logistic regression analysis, DM duration (odds ratio [OR]: 0.907; 95% confidence interval [CI]: 0.842-0.977; P = 0.01), diabetic retinopathy (OR: 0.196; 95% CI: 0.061-0.627; P = 0.006), and urinary RBC (OR: 1.068; 95% CI: 1.024-1.115; P = 0.002) were independent predictors of NDRD. In patients with diabetic retinopathy (n = 112, 70%), the presence of proliferative diabetic retinopathy, pan-retinal photocoagulation, and hematuria were factors predicting NDRD; and in patients without diabetic retinopathy (n = 48, 30%), short DM duration and hematuria were factors predicting NDRD. CONCLUSIONS: Using diabetic retinopathy, DM duration, and hematuria, we developed a 3-step approach to stratify patients into three categories with the different likelihoods of having NDRD. Then different strategies could be taken accordingly. Our stepwise approach is easy to follow and may serve as an appropriate and useful tool to help clinicians in making decisions of kidney biopsy in type 2 DM patients presenting with kidney diseases.